Washing machine

ABSTRACT

The invention provides a washing machine ( 10 ) operable even in the presence of a great eccentric load and exhibiting an outstanding vibration attenuating effect by suppressing eccentricity even if laundry in a drum ( 30 ) is in an unbalanced position. The washing machine ( 10 ) comprises an inner drum ( 30 ) having a rotatably supported axis and a closed wall at at least one end thereof, and a plurality of liquid holding boxes ( 35 ) provided on the closed wall of the inner drum ( 30 ) externally thereof and each having an opening facing toward the axis. The periphery of the inner drum ( 30 ) is provided with hollow liquid holding tubes ( 37 ) communicating with the respective liquid holding boxes ( 35 ).

TECHNICAL FIELD

[0001] The present invention relates to washing machines wherein the vibration of a drum to be produced by an unbalanced condition of laundry can be suppressed.

BACKGROUND ART

[0002] With washing machines wherein an inner drum for placing laundry therein is positioned to face toward a horizontal direction, the drum is likely to rotate for the extraction of water, with the laundry in an unbalanced condition inside the drum owing to a centrifugal force. The inner drum is then brought out of balance under gravity, producing vibration or noise with the rotation of the drum.

[0003] Accordingly, a washing machine 10 is proposed wherein an inner drum 30 is provided with a plurality of liquid holding boxes 35, 35 on a closed wall thereof as shown in FIG. 10. The washing machine 10 has a water conduit 60 for supplying tap water to the liquid holding boxes 35, and water is supplied to the boxes 35 via the conduit 60 to alter the amounts of water to be held in the boxes 35 in accordance with the degree of eccentricity of the laundry and to restrain the drum from rotating eccentrically.

[0004] The liquid holding boxes 35 are arranged at one end of the drum 30 and therefore limited in size. This entails the problem that the amount of water to be accommodated in the liquid holding box is limited to impose limitations on the eccentric loads to be held in balance.

[0005] Further if laundry S is positioned toward the opening end of the drum 30 as shown in FIG. 10, the laundry S is axially away from the liquid holding boxes 35, so that even if the amounts of water in the boxes 35 are altered, the axis of the drum 30 will deflect to result in the problem that the eccentricity can not be fully suppressed.

[0006] An object of the present invention is to provide a washing machine which is adapted to overcome the problems due to a great eccentric load and which is diminished in eccentricity even if the laundry is positioned toward one side unevenly in the drum.

DISCLOSURE OF THE INVENTION

[0007] To fulfill the above object, the present invention provides a washing machine comprising an inner drum having a rotatably supported axis and a closed wall at at least one end thereof, and a plurality of liquid holding boxes provided on the closed wall of the inner drum externally thereof and each having an opening facing toward the axis. The periphery of the inner drum is provided with hollow liquid holding tubes communicating with the respective liquid holding boxes.

[0008] Since the liquid holding tubes are provided in the washing machine of the invention in communication with the respective liquid holding boxes, a liquid can be held in the tubes, and a greater amount of liquid can be accommodated in the machine than in the prior art. The washing machine is therefore operable even in the presence of a great eccentric load.

[0009] Further the use of the liquid holding tubes makes it possible to bring the inner drum into weight balance not only at one end of the drum where the liquid holding boxes are provided on the closed wall of the drum but also over the length of the inner drum. Accordingly, the drum exhibits an outstanding vibration attenuating effect even if the laundry is unevenly positioned at one end of the drum opposite to the closed wall provided with the liquid holding boxes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a side elevation in section showing the overall construction of a washing machine of the invention.

[0011]FIG. 2 is a view in section taken along the line II-II in FIG. 1 and showing an inner drum.

[0012]FIG. 3 is a side elevation in section and showing the washing machine while bringing the drum into weight balance.

[0013]FIG. 4 is a block diagram showing the electric system of the washing machine of the invention.

[0014]FIG. 5 is a side elevation in section showing the overall construction of a washing machine as a different embodiment of the invention.

[0015]FIG. 6 is a view in section taken along the line VI-VI in FIG. 5 and showing an inner drum.

[0016]FIG. 7 is a perspective view showing the shapes of a liquid holding box and a liquid holding tube.

[0017]FIG. 8 is a perspective view showing a liquid holding box and a liquid holding tube which have a water passage hole of altered shape.

[0018]FIG. 9 is a sectional view showing an embodiment of air vent member.

[0019]FIG. 10 is a side elevation in section of a conventional washing machine.

BEST MODE OF CARRYING OUT THE INVENTION

[0020] <Embodiment 1>

[0021] A washing machine 10 of the present invention will be described with reference to FIGS. 1 and 2.

[0022]FIG. 1 is a side elevation in section showing the overall construction of the washing machine 10 of the invention. The washing machine 10 of the invention comprises a cabinet 12 serving as an enclosing frame and a washtub 20 housed in the cabinet for washing and rinsing laundry and extracting water therefrom.

[0023] The washtub 20 comprises an inner drum 30 for placing laundry thereinto, and an outer tub 40 enclosing the inner drum 30 therein.

[0024] The inner drum 30 has an opening 31 formed in one end thereof for placing laundry into the drum therethrough and a closed wall at the other end thereof. A rotation shaft 32 is attached to the outer side of the closed wall centrally thereof. An inner drum is also available which has an opening formed in the peripheral wall thereof for placing laundry into the drum therethrough and is closed at opposite ends thereof. The present invention is applicable also to a washing machine comprising such an inner drum.

[0025] The drum 30 has its rotation shaft 32 rotatably supported by the outer tub 40. Preferably, the drum 30 has its rotation shaft 32 supported substantially horizontally or as inclined. The shaft 32 extends through the outer tub 40 to the outside and is provided with a pulley 33 at the outer end thereof.

[0026] The inner drum 30 has a plurality of drain holes (not shown) formed in an inner peripheral wall thereof and a plurality of projecting baffles 34, 34 arranged in parallel to its axis for scraping up the laundry as shown in FIGS. 1 and 2. Each of the baffles 34 of the illustrated embodiment has a generally triangular cross section and is provided with a hollow liquid holding tube 37 inside thereof. The tube 37 is in communication with a liquid holding box 35 to be described below. The baffles 34 and liquid holding tubes 37 are not limited to those of the illustrated embodiment with respect to the shape, size and number.

[0027] As shown in FIG. 1, the inner drum 30 is provided at the closed end thereof with liquid holding boxes 35, 35 as positioned in corresponding relation with the respective liquid holding tubes 37, 37 within the baffles 34, 34. Each liquid holding box 35 has an opening facing toward the rotation shaft 32. The box 35 communicates with the corresponding tube 37 through a water passage hole 36 formed in the closed end wall of the drum 30.

[0028] The outer tub 40 is a cylinder which has an opening at the same end as the drum 30. The opening is provided with an openable closure 41 for closing the outer tub 40.

[0029] The outer tub 40 is supported by being suspended from the top of the cabinet 12 by springs 42, 42, and is supported at its bottom by dampers 43, 43 so as to attenuate the vibration to be produced with the rotation of the drum 30.

[0030] The outer tub 40 is further provided with a water injection pipe (not shown) for supplying washing water to the drum 30 and a drain pipe (not shown) for draining the drum. These pipes are each provided with a valve.

[0031] A motor 50 is attached to the outer periphery of the outer tub 40 and coupled to the pulley 33 of the drum 30 by a belt 51. When rotated, the motor 50 rotates the drum 30 inside the outer tub 40.

[0032] A water conduit 60 for supplying a liquid (i.e., water in the present embodiment) to the liquid holding box 35 extends into the outer tub 40 to a position slightly below the rotation shaft 32. Water is discharged from the conduit or stopped under the control of a water supply valve 61. The water conduit 60 extends outward from the cabinet 12 and is connected to a faucet of a water supply pipe. Inside the outer tub 40, the outer end of the water conduit 60 is bent downward to supply tap water as indicated at W1 to the liquid holding box 35 as positioned under the conduit 60 as shown in FIG. 1. The water W supplied to the box 35 partly flows through the water passage hole 36 into the liquid holding tube 37.

[0033] When the drum 30 is rotated at a low speed so that gravity acts more strongly than a centrifugal force acting on the water W, the liquid holding box 35 passing the upper side and the corresponding liquid holding tube 37 can be drained of water W as indicated at W2 as shown in FIG. 3.

[0034] The washing machine 10 is provided with a sensor for detecting an unbalanced condition or eccentricity of the laundry inside the inner drum 30. An encoder 53 serving as the sensor is mounted on the rotation shaft 32 of the drum 30 for detecting irregularities involved in the rotation of the drum 30. The sensor to be used may be a vibration sensor (not shown) for detecting the vibration of the outer tub 40. The vibration sensor can be provided by a magnetostrictive sensor or load cell.

[0035] The washing machine 10 of the above construction has an electric system, which will be described with reference to the block diagram of FIG. 4.

[0036] All control operations for the washing machine 10 are conducted by control means 7. The control means 7, which is disposed in a suitable portion of the washing machine 10, consists mainly of a microcomputer 70. The microcomputer 70 includes a CPU, memories, calculating circuit, etc. and has connected thereto a motor drive circuit 71 for controlling the rotation of the motor 50, a valve control circuit 72 for controlling a water injection valve 44, drain valve 45 and the water supply valve 61, a sensor circuit 73 for detecting trigger pulses of an encoder 53, etc. The microcomputer 70 calculates the rotational angular velocity of the drum 30 from trigger pulses input from the sensor circuit 73 to detect the position of eccentricity of the laundry.

[0037] The microcomputer 70 has incorporated therein a memory (not shown) having laundering programs stored therein, and a memory having stored therein positions of eccentricity of laundry and optimum quantities of water in the liquid holding boxes 35 and liquid holding tubes 37.

[0038] Also connected to the microcomputer 70 are other units, i.e., a manual unit 74 to be manipulated by the user for giving instructions, and a display unit 75 for displaying the state of the washing machine 10, results of manipulations, progress of laundering operation, remaining periods of time, suitable amounts of detergent, etc.

[0039] With laundry placed into the inner drum 30, the washing machine 10 of the above construction is operated for washing and rinsing the laundry, draining the drum and thereafter extracting water from the laundry.

[0040] For the extraction of water, the drum 30 is rotated with the drain valve opened.

[0041] The extraction of water can be conducted by the preliminary step of extracting water, step of correcting weight balance and main step of extracting water.

[0042] Preliminary Step of Extracting Water

[0043] The inner drum 30 is rotated with the drain valve left open and with the speed of rotation set at a medium value (a speed at which the centrifugal force acting on the water W is greater than the gravity acting thereon, e.g., 100 rpm) for preliminary extraction of water from the laundry S. At this time, the water supply valve 61 on the water conduit 60 is left open at the same time to fill water W1 into the liquid holding boxes 35 and the liquid holding tubes 37 as shown in FIG. 1.

[0044] When the inner drum 30 is rotated, the laundry is centrifugally adhered to the inner surface of the drum 30. The position of eccentricity of the laundry S is detected by detecting the pulses of the encoder 53. If the unbalanced condition of the laundry is within a permissible range, the subsequent step may be omitted.

[0045] Step of Correcting Weight Balance

[0046] After the position of eccentricity of the laundry S has been detected, the quantities of water W in the liquid holding tube 37 and the liquid holding box 35 corresponding to the position of eccentricity are reduced to bring the drum substantially into weight balance. The amounts of water in the box 35 and tube 37 can be reduced by slowing down the motor 50 when the box 35 corresponding to the position of eccentricity moves past the upper side and decreasing the speed of rotation of the drum 30 (for example, to 40 rpm). The motor 50 as slowed down permits the water W2 to fall off from the box 35 moving past the upper side to reduce the amounts of water in the box 35 and tube 37.

[0047] The motor 50 is so controlled as to drain the corresponding box 37 and tube 35 of water until substantially uniform weight balance is attained with reference to pulses of the encoder 53.

[0048] When the inner drum 30 is brought generally into weight balance, extraction of water follows. If the drum can not be substantially brought into balance even if the corresponding tube 37 and box 35 have been completely drained of water, the drum 30 maybe brought out of rotation once to resume the preliminary water extraction step, or an error display is presented on the display unit 75 to discontinue the extraction of water.

[0049] Main Step of Extracting Water

[0050] After the drum 30 is brought into corrected weight balance, the motor 50 is speeded up to rotate the drum 30 at a high speed (e.g., 1000 rpm). The high-speed rotation of the drum 30 releases the water of the laundry into the outer tub 40 through the drain holes for the extraction of water. Because of the corrected weight balance, the vibrations to be produced with the rotation of the drum 30 are also attenuated.

[0051] After the completion of water extraction, the motor 50 is brought out of rotation, permitting the drum 30 to rotate through inertia as decelerated gradually, so that the water falls off from all the boxes 35 and tubes 37 and is discharged.

[0052] <Embodiment 2>

[0053] A different embodiment of liquid holding tube 37 will be described.

[0054] With reference to FIGS. 5 and 6, the liquid holding tube 37 of this embodiment is so inclined that one end thereof toward the closed end wall of the inner drum 30 is positioned closer to the axis of the drum 30. In conformity with the inclination of the tube 37, the baffle 34 is also so inclined that one end thereof toward the closed drum end wall is positioned closer to the axis of the drum 30.

[0055] Thus, one end of the tube 37 where the water passage hole 36 is formed is positioned closer to the axis of the drum 30, whereby the liquid can be caused to flow into and out of the liquid holding tube 37 efficiently. Accordingly, the adjustment for bringing the drum 30 into weight balance can be made within a shorter period of time than is the case with Embodiment 1.

[0056] <Embodiment 3>

[0057] A description will be given of an embodiment of liquid holding box 35 which has a desirable shape and a water passage hole 36 of preferred shape.

[0058] Shape of Liquid Holding Box

[0059] The liquid holding box 35 can be so shaped as to be tapered toward the axis of the drum 30 as shown in FIG. 7. Preferably, an opening 35 a of the box is partly provided with a lid 35 b so as to prevent water from falling off from the box 35 in an excessive amount. The lid 35 b is positioned preferably toward the direction of rotation of the drum 30, and can be L-shaped for example.

[0060] Further as shown in FIG. 7, the opening of the liquid holding box 35 is provided with a cutout 35 c, whereby the box 35 can be drained of water with an improved efficiency.

[0061] Shape of Water Passage Hole

[0062] With reference to FIG. 7, the water passage hole 36 for holding the box 35 and the tube 37 in communication with each other can be provided by a pipe member 37 a.

[0063]FIG. 8 shows a liquid holding tube 37 having one end which is almost entirely opened, and an opening 35 d corresponding to the opening 37 a of the tube 37 is formed in the portion of the box 35 to be connected to the tube. The openings 37 a, 35 d of the tube 37 and the box 35 can then be caused to communicate with each other directly. In this case, a larger amount of liquid can be caused to flow between the box 35 and the tube 37 than when the pipe member is used. Accordingly, the adjustment for bringing the inner drum 30 into weight balance can be made within a shorter period of time.

[0064] Provision of Silencer Plate

[0065] It is desired that a silencer plate 38 be provided in the interior of the liquid holding box 35 as shown in FIG. 7 so as to reduce the noise to be produced when the liquid flows into or out of the box 35. With reference to FIG. 7, the silencer plate 38 can be provided by a plate having a plurality of holes 38 a, 38 a. The silencer plate 38 can be disposed, for example, below the lid 35 b so as not to interfere with the flow of liquid into or out of the box 35.

[0066] The silencer plate 38 serves to abate the noise to be produced by the flow of liquid when an adjustment is made to bring the drum 30 into weight balance.

[0067] Provision of Air Vent Member

[0068] It is desired that the liquid holding tube 37 be provided with an air vent member 39 extending from inside thereof to the outside as shown in FIG. 9 so as to permit the liquid to flow into the tube 37 with a higher efficiency. The air vent member 39 can be provided by a tubular member as shown in FIG. 9. The tubular member can be made from a flexible material. Preferably, the tubular member is so disposed that one end thereof is in communication with the interior of the tube 37, with the other end thereof extending outward from the opening 35 a of the box 35. The air vent member may be provided between the closed side of the tube 37 and the outside.

[0069] The air inside the liquid holding tube 37 is discharged through the air vent member 39 when the liquid flows into the tube 37. This eliminates the likelihood that the air will remain inside the tube 37 to interfere with the inflow of the liquid. Further the tube 37 can be drained of the liquid also efficiency since air is sent into the tube 37 through the vent member 39 when the liquid is discharged from inside the tube 37.

[0070] The liquid holding tube 37 is provided inside the baffle 34 according to the foregoing embodiments, whereas the tube 37 can be provided on the outer periphery of the inner drum 30. In this case, the baffle 34 may be formed when required.

[0071] Preferably, the liquid holding tube 37 is provided over at least one half of the length of the drum 30. Most preferably, the tube 37 is provided over the entire length of the drum.

[0072] Although water is exemplified as the liquid to be placed into the liquid holding boxes 35 and liquid holding tubes 37, other liquid can be used alternatively. The weight balance of the drum can be controlled more effectively in this case by using, for example, an aqueous solution of calcium chloride (1.3 in specific gravity) which is greater than water in specific gravity.

[0073] The embodiments described above are intended to illustrate the present invention and should not be construed as limiting the invention set forth in the appended claims or reducing the scope thereof. The machine of the invention is not limited to the foregoing embodiments in construction but can be modified variously within the technical scope defined in the claims.

INDUSTRIAL APPLICABILITY

[0074] The present invention provides a useful washing machine operable even in the presence of a great eccentric load and having an outstanding vibration attenuating effect. 

1. A washing machine comprising an inner drum having a rotatably supported axis and a closed wall at at least one end thereof, and a plurality of liquid holding boxes provided on the closed wall of the inner drum externally thereof and each having an opening facing toward the axis, the washing machine being characterized in that the inner drum is provided at a periphery thereof with hollow liquid holding tubes communicating with the respective liquid holding boxes.
 2. The washing machine according to claim 1 wherein the liquid holding tubes are provided in parallel to the axis of the inner drum.
 3. The washing machine according to claim 1 wherein each of the liquid holding tubes is so inclined that one end thereof toward the closed wall is positioned closer to the axis of the inner drum.
 4. The washing machine according to any one of claims 1 to 3 wherein an inner peripheral wall of the inner drum is provided with baffles in parallel to the axis for scraping up laundry, and the liquid holding tubes are formed inside the respective baffles.
 5. The washing machine according to any one of claims 1 to 4 wherein the liquid holding tubes are each provided with an air vent member for assisting a liquid to flow into or out of the liquid holding tube.
 6. The washing machine according to claim 5 wherein the air vent member is a tubular member having one end in communication with inside of the liquid holding tube and the other end extending outward from the opening of the corresponding liquid holding box.
 7. The washing machine according to any one of claims 1 to 6 wherein each of the liquid holding boxes has a lid provided over a portion of the opening facing toward the axis of the inner drum.
 8. The washing machine according to any one of claims 1 to 7 wherein each of the liquid holding boxes communicates with the corresponding liquid holding tube through a pipe member.
 9. The washing machine according to any one of claims 1 to 7 wherein each of the liquid holding tubes has one end positioned close to the closed wall and entirely opened, and each of the liquid holding boxes has an opening to be held in communication with the entire opening of the corresponding liquid holding tube, these two openings being in direct communication with each other to cause the liquid holding tube to communicate with the liquid holding box.
 10. The washing machine according to any one of claims 1 to 9 wherein the liquid holding boxes are each provided inside thereof with a silencer plate for reducing the noise to be produced by a flow of liquid. 